SigRec: Automatic Recovery of Function Signatures in Smart Contracts

Millions of smart contracts have been deployed onto Ethereum for providing various services, whose functions can be invoked. For this purpose, the caller needs to know function signature a callee, which includes its id and parameter types. Such signatures are critical many applications focusing on contracts, e.g., reverse engineering, fuzzing, attack detection, profiling. Unfortunately, it is challenging recover from contract bytecode, since neither debug information nor type present in bytecode. To address issue, prior approaches rely source code, or collection known incomplete databases heuristic rules, which, however, far adequate cannot cope with rapid growth new contracts. In paper, we propose novel solution that leverages how handled by virtual machine (EVM) automatically signatures. particular, exploit determine invoked locate extract ids, approach named type-aware symbolic execution (TASE) utilizes semantics EVM operations parameters identify number types parameters. Moreover, develop SigRec, tool recovering bytecode without need code databases. The extensive experimental results show SigRec outperforms all existing tools, achieving an unprecedented 98.7 percent accuracy within 0.074 seconds. We further demonstrate recovered useful fuzzing engineering